tools: add physinfo arch_capabilities handling for Arm

On Arm, the SVE vector length is encoded in arch_capabilities field
of struct xen_sysctl_physinfo, make use of this field in the tools
when building for arm.

Create header arm-arch-capabilities.h to handle the arch_capabilities
field of physinfo for Arm.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>

tools/golang/xenlight/helpers.gen.go

@@ -3506,6 +3506,7 @@ x.CapVmtrace = bool(xc.cap_vmtrace)
 x.CapVpmu = bool(xc.cap_vpmu)
 x.CapGnttabV1 = bool(xc.cap_gnttab_v1)
 x.CapGnttabV2 = bool(xc.cap_gnttab_v2)
+x.ArchCapabilities = uint32(xc.arch_capabilities)
 
  return nil}
 
@@ -3540,6 +3541,7 @@ xc.cap_vmtrace = C.bool(x.CapVmtrace)
 xc.cap_vpmu = C.bool(x.CapVpmu)
 xc.cap_gnttab_v1 = C.bool(x.CapGnttabV1)
 xc.cap_gnttab_v2 = C.bool(x.CapGnttabV2)
+xc.arch_capabilities = C.uint32_t(x.ArchCapabilities)
 
  return nil
  }

tools/golang/xenlight/types.gen.go

@@ -1079,6 +1079,7 @@ CapVmtrace bool
 CapVpmu bool
 CapGnttabV1 bool
 CapGnttabV2 bool
+ArchCapabilities uint32
 }
 
 type Connectorinfo struct {

tools/include/libxl.h

@@ -525,6 +525,12 @@
  */
 #define LIBXL_HAVE_PHYSINFO_CAP_GNTTAB 1
 
+/*
+ * LIBXL_HAVE_PHYSINFO_ARCH_CAPABILITIES indicates that libxl_physinfo has a
+ * arch_capabilities field.
+ */
+#define LIBXL_HAVE_PHYSINFO_ARCH_CAPABILITIES 1
+
 /*
  * LIBXL_HAVE_MAX_GRANT_VERSION indicates libxl_domain_build_info has a
  * max_grant_version field for setting the max grant table version per

tools/include/xen-tools/arm-arch-capabilities.h

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: LGPL-2.1-only */
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#ifndef ARM_ARCH_CAPABILITIES_H
+#define ARM_ARCH_CAPABILITIES_H
+
+#include <stdint.h>
+#include <xen/sysctl.h>
+
+#include <xen-tools/common-macros.h>
+
+static inline
+unsigned int arch_capabilities_arm_sve(unsigned int arch_capabilities)
+{
+#if defined(__aarch64__)
+    unsigned int sve_vl = MASK_EXTR(arch_capabilities,
+                                    XEN_SYSCTL_PHYSCAP_ARM_SVE_MASK);
+
+    /* Vector length is divided by 128 before storing it in arch_capabilities */
+    return sve_vl * 128U;
+#else
+    return 0;
+#endif
+}
+
+#endif /* ARM_ARCH_CAPABILITIES_H */

tools/include/xen-tools/common-macros.h

@@ -72,6 +72,8 @@
 #define ROUNDUP(_x,_w) (((unsigned long)(_x)+(1UL<<(_w))-1) & ~((1UL<<(_w))-1))
 #endif
 
+#define MASK_EXTR(v, m) (((v) & (m)) / ((m) & -(m)))
+
 #ifndef __must_check
 #define __must_check __attribute__((__warn_unused_result__))
 #endif

tools/libs/light/libxl.c

@@ -409,6 +409,7 @@ int libxl_get_physinfo(libxl_ctx *ctx, libxl_physinfo *physinfo)
         !!(xcphysinfo.capabilities & XEN_SYSCTL_PHYSCAP_gnttab_v1);
     physinfo->cap_gnttab_v2 =
         !!(xcphysinfo.capabilities & XEN_SYSCTL_PHYSCAP_gnttab_v2);
+    physinfo->arch_capabilities = xcphysinfo.arch_capabilities;
 
     GC_FREE;
     return 0;

tools/libs/light/libxl_internal.h

@@ -132,7 +132,6 @@
 
 #define DIV_ROUNDUP(n, d) (((n) + (d) - 1) / (d))
 
-#define MASK_EXTR(v, m) (((v) & (m)) / ((m) & -(m)))
 #define MASK_INSR(v, m) (((v) * ((m) & -(m))) & (m))
 
 #define LIBXL__LOGGING_ENABLED

tools/libs/light/libxl_types.idl

@@ -1133,6 +1133,7 @@ libxl_physinfo = Struct("physinfo", [
     ("cap_vpmu", bool),
     ("cap_gnttab_v1", bool),
     ("cap_gnttab_v2", bool),
+    ("arch_capabilities", uint32),
     ], dir=DIR_OUT)
 
 libxl_connectorinfo = Struct("connectorinfo", [

tools/ocaml/libs/xc/xenctrl.ml

@@ -128,12 +128,10 @@ type physinfo_cap_flag =
   | CAP_Gnttab_v1
   | CAP_Gnttab_v2
 
-type arm_physinfo_cap_flag
-
 type x86_physinfo_cap_flag
 
 type arch_physinfo_cap_flags =
-  | ARM of arm_physinfo_cap_flag list
+  | ARM of int
   | X86 of x86_physinfo_cap_flag list
 
 type physinfo =

tools/ocaml/libs/xc/xenctrl.mli

@@ -113,12 +113,10 @@ type physinfo_cap_flag =
   | CAP_Gnttab_v1
   | CAP_Gnttab_v2
 
-type arm_physinfo_cap_flag
-
 type x86_physinfo_cap_flag
 
 type arch_physinfo_cap_flags =
-  | ARM of arm_physinfo_cap_flag list
+  | ARM of int
   | X86 of x86_physinfo_cap_flag list
 
 type physinfo = {

tools/ocaml/libs/xc/xenctrl_stubs.c

@@ -851,13 +851,15 @@ CAMLprim value stub_xc_physinfo(value xch_val)
 	arch_cap_list = Tag_cons;
 
 	arch_cap_flags_tag = 1; /* tag x86 */
-#else
-	caml_failwith("Unhandled architecture");
-#endif
 
 	arch_cap_flags = caml_alloc_small(1, arch_cap_flags_tag);
 	Store_field(arch_cap_flags, 0, arch_cap_list);
 	Store_field(physinfo, 10, arch_cap_flags);
+#elif defined(__aarch64__)
+	Store_field(physinfo, 10, Val_int(c_physinfo.arch_capabilities));
+#else
+	caml_failwith("Unhandled architecture");
+#endif
 
 	CAMLreturn(physinfo);
 }

tools/python/xen/lowlevel/xc/xc.c

@@ -22,6 +22,7 @@
 #include <xen/hvm/hvm_info_table.h>
 #include <xen/hvm/params.h>
 
+#include <xen-tools/arm-arch-capabilities.h>
 #include <xen-tools/common-macros.h>
 
 /* Needed for Python versions earlier than 2.3. */
@@ -871,6 +872,7 @@ static PyObject *pyxc_physinfo(XcObject *self)
     const char *virtcap_names[] = { "hvm", "pv" };
     const unsigned virtcaps_bits[] = { XEN_SYSCTL_PHYSCAP_hvm,
                                        XEN_SYSCTL_PHYSCAP_pv };
+    PyObject *objret;
 
     if ( xc_physinfo(self->xc_handle, &pinfo) != 0 )
         return pyxc_error_to_exception(self->xc_handle);
@@ -897,17 +899,35 @@ static PyObject *pyxc_physinfo(XcObject *self)
     if ( p != virt_caps )
       *(p-1) = '\0';
 
-    return Py_BuildValue("{s:i,s:i,s:i,s:i,s:l,s:l,s:l,s:i,s:s,s:s}",
+    objret = Py_BuildValue("{s:i,s:i,s:i,s:i,s:l,s:l,s:l,s:i,s:s,s:s}",
-                            "nr_nodes",         pinfo.nr_nodes,
+                           "nr_nodes",         pinfo.nr_nodes,
-                            "threads_per_core", pinfo.threads_per_core,
+                           "threads_per_core", pinfo.threads_per_core,
-                            "cores_per_socket", pinfo.cores_per_socket,
+                           "cores_per_socket", pinfo.cores_per_socket,
-                            "nr_cpus",          pinfo.nr_cpus,
+                           "nr_cpus",          pinfo.nr_cpus,
-                            "total_memory",     pages_to_kib(pinfo.total_pages),
+                           "total_memory",     pages_to_kib(pinfo.total_pages),
-                            "free_memory",      pages_to_kib(pinfo.free_pages),
+                           "free_memory",      pages_to_kib(pinfo.free_pages),
-                            "scrub_memory",     pages_to_kib(pinfo.scrub_pages),
+                           "scrub_memory",     pages_to_kib(pinfo.scrub_pages),
-                            "cpu_khz",          pinfo.cpu_khz,
+                           "cpu_khz",          pinfo.cpu_khz,
-                            "hw_caps",          cpu_cap,
+                           "hw_caps",          cpu_cap,
-                            "virt_caps",        virt_caps);
+                           "virt_caps",        virt_caps);
+
+#if defined(__aarch64__)
+    if ( objret ) {
+        unsigned int sve_vl_bits;
+        PyObject *py_arm_sve_vl;
+
+        sve_vl_bits = arch_capabilities_arm_sve(pinfo.arch_capabilities);
+        py_arm_sve_vl = PyLong_FromUnsignedLong(sve_vl_bits);
+
+        if ( !py_arm_sve_vl )
+            return NULL;
+
+        if( PyDict_SetItemString(objret, "arm_sve_vl", py_arm_sve_vl) )
+            return NULL;
+    }
+#endif
+
+    return objret;
 }
 
 static PyObject *pyxc_getcpuinfo(XcObject *self, PyObject *args, PyObject *kwds)

tools/xl/xl_info.c

@@ -27,6 +27,7 @@
 #include <libxl_json.h>
 #include <libxl_utils.h>
 #include <libxlutil.h>
+#include <xen-tools/arm-arch-capabilities.h>
 
 #include "xl.h"
 #include "xl_utils.h"
@@ -224,6 +225,13 @@ static void output_physinfo(void)
          info.cap_gnttab_v2 ? " gnttab-v2" : ""
         );
 
+    /* Print arm SVE vector length only on ARM platforms */
+#if defined(__aarch64__)
+    maybe_printf("arm_sve_vector_length  : %u\n",
+         arch_capabilities_arm_sve(info.arch_capabilities)
+        );
+#endif
+
     vinfo = libxl_get_version_info(ctx);
     if (vinfo) {
         i = (1 << 20) / vinfo->pagesize;